A variety of mail processing and handling devices and systems utilize ink jet printing technology to print information, such as, without limitation, various images, postal indicia (which may include a two-dimensional barcode) and address information, on mailpieces. For example, inserter systems used by organizations such as banks, insurance companies, and utility companies for producing large volume mailings often use ink jet printing technology to print such information on the mailpieces that are being prepared. Such inserter systems resemble an assembly line and transport the mailpieces to a number of different workstations, which may include one or more printing stations, to cooperatively produce finished mailpieces.
Ink jet printers are well known in the art, and generally include one or more arrays of nozzles (sometimes referred to as orifices), a supply of ink, a plurality of ejection elements (for example, expanding vapor bubble elements or piezoelectric transducer elements) corresponding to the nozzles and suitable driver and control electronics (referred to as a print head controller) for controlling the ejection elements. Typically, the one or more arrays of nozzles and the ejection elements along with their associated components are referred to as a print head. It is the activation of the ejection elements that causes drops of ink to be expelled from the nozzles toward the print medium to collectively form a print image.
Because ink jet printing technology inherently has a narrow depth of field requirement in order to obtain an acceptable image, printing on mailpieces or other media using ink jet printing technology requires that the media be accurately positioned such that the surface to be printed is spaced from the print nozzles of the print head within a narrow range. This distance range may need to be held, for example, to between approximately 0.04 inches to approximately 0.08 inches. If the distance between the print head and the media surface varies out of the specified range, the printed image that results will likely be of poor quality and often deemed unacceptable.
Thus, maintaining the proper distance between the print head and the surface of a medium may be significant in mail processing devices and systems, where the thickness of mailpieces may vary from approximately 0.06 inches to approximately 2 inches. Mailpieces may also require higher printing resolutions to produce more advanced graphics.